Frame structure of a printer with positioning openings

Abstract

A printing apparatus such as a printer of the type using a type wheel includes two guide members which extend between a pair of side frames and each of which is fixed by riveting. A carrier is slidably mounted on the guide members. A carriage loaded with a type wheel and others is mounted on a carrier in such a manner as to be rotatable by 90 degrees between a predetermined print position and a wheel replace position behind the print position. A sensor for determining the presence/absence and the kind of a type wheel loaded in the carriage is provided.

What is claimed is: 
     
       1. A printing apparatus having a platen, comprising: a pair of side frames (11, 12);   a guide member (13) extending between said side frames;   a carriage loaded with a printing mechanism and slidably supported by said guide member to move along the platen; and   a stay (14) interconnecting said side frames (11, 12), said stay (14) being provided with lugs (14a) which are integral therewith for engaging said side frames (11, 12);   said side frames (11, 12) being individually provided with positioning openings (15, 16 and/or 21) each mating with a respective one of positioning pins (34, 35 and/or 36) which are provided on a supporting member (31) for temporarily supporting said side frames (11, 12) at the time when said stay (14) and said side frames (11, 12) are to be fixed in an interconnected condition, and said stay (14) being provided with positioning holes (14b) mating with a respective one of positioning pins (33) which are provided on said supporting member (31), to thereby temporarily affix said side frames (11, 12) and said stay (14) relative to each other for assembly with each other.   
     
     
       2. A printing apparatus as claimed in claim 1, wherein each of said side frames is each provided with a plurality of openings (20) with which said integral lugs (14a) individually mate, said lugs (14a) protruding outwardly from said side frames (11, 12) while said side frames are pressed toward each other to thereby sqeeze said lugs (14a) while said side frames are temporarily supported by the mating of said pins with said positioning openings and positioning holes. 
     
     
       3. A printing apparatus as claimed in claim 1, wherein each of said side frames comprises a sheet metal. 
     
     
       4. A printing apparatus as claimed in claim 1, wherein said printing mechanism includes a type wheel and a hammer. 
     
     
       5. A printing apparatus as in claim 2 in which said stay (14) has a bent configuration to increase the mechanical strength thereof. 
     
     
       6. A printing apparatus as in claim 2 in which said side frames (11, 12) are provided with guide member receiving holes (16) and said guide member (13) which slidably supports said carriage is fixed in place relative to said side frames (11, 12) by engaging said guide member receiving holes. 
     
     
       7. A printing apparatus as in claim 2 in which said side frames (11, 12) and said stay (14) are affixed by said supporting member (31) for assembly in a position in which said side frames are perpendicular to said stay.